HI-8581

HI-8581 June 2001 GENERAL DESCRIPTION The HI-8581 device from Holt Integrated Circuits is a silicon gate CMOS device for interfacing a 16-bit parallel data bus directly to the ARINC 429 serial bus. The device provides two receivers, an independent transmitter and line driver capability in a single package. The receiver input circuitry and logic are designed to meet the ARINC 429 specifications for loading, level detection, timing, and protocol. The transmitter section provides the ARINC 429 communication protocol and the line driver circuits provide the ARINC 429 output levels. The 16-bit parallel data bus exchanges the 32-bit ARINC data word in two steps when either loading the transmitter or interrogating the receivers. The data bus interfaces with CMOS and TTL. Timing of all the circuitry begins with the master clock input, CLK. For ARINC 429 applications, the master clock frequency is 1 MHz. Each independent receiver monitors the data stream with a sampling rate 10 times the data rate. The sampling rate is software selectable at either 1MHz or 125KHz. The results of a parity check are available as the 32nd ARINC bit. The HI-8581 examines the null and data timings and will reject erroneous patterns. For example, with a 125 KHz clock selection, the data frequency must be between 10.4 KHz and 15.6 KHz. The transmitter has a First In, First Out (FIFO) memory to store 8 ARINC words for transmission. The data rate of the transmitter is software selectable by dividing the maste...